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hard disk: A storage device composed of a rigid platter or platters that store information
magnetically. Hard disks hold much more information than diskettes and are
used for the long-term storage of programs and data. The primary (or only)
hard disk in a personal computer is usually fixed, but some computers have
secondary hard disks that are removable. In a server, all hard disks may be
removable. By default, the primary hard disk is referred to as drive C.
hardware: The physical, electronic and mechanical components of a computer system,
including devices such as a screen, disk drive, printer, mouse and processor.
hexadecimal: The base-16 numbering system used by programmers to represent binary
numbers. Digits above 9 are represented by letters (the 15 digits are 1, 2, 3, 4,
5, 6, 7, 8, 9, A, B, C, D, E and F). Two hexadecimal digits are equivalent to the
eight bits in a byte. For example, F1 in hexadecimal is equivalent to 11110001
in binary. See also binary, decimal.
high-density diskette: A diskette that holds 1.2 MB (5.25-inch) or 1.44 MB (3.5-inch) of
information.
hot-swappable drives: Drives that you can install or remove without using screws or
cables and without powering down the server.
hub: A central connecting device in a network that joins communications lines together in
a star configuration. A switching hub also routes messages and packets
among the computers connected to the network.
hypermedia: A method of providing multiple connected pathways through a body of
information, allowing users to jump easily from a topic to related or
supplementary material, which may be text, graphics, audio, images or video.
HyperText Markup Language (HTML): A special coding scheme used to prepare text and
graphics for access over the World Wide Web.
I
icon: A small picture that represents a function, file, or program.
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